A technique for acquiring the state of a person (moving body) through a body-worn system is essential to the realization of an intellectual interface with a computer through a grasp of context information on the person. Such a technique is expected to be developed to have many applications in pedestrian navigation, grasping of the situation of workers during remote operation assistance, guiding of visitors thorough exhibitions in museums or large-scale exhibition facilities, etc.
For example, an attitude angle processing apparatus that is taken along by a person to be able to give accurate information on the attitude angle of that person is worn by an object to be measured (a small-sized device such as a cellular phone or a PDA, a human body, etc.) to acquire the attitude angle of the object to be measured as a signal from a group of small-sized, lightweight, and inexpensive sensors.
Conventionally, a technique for acquiring an absolute attitude angle by using either a magnetic sensor and an angle-of-inclination sensor or a gravitational acceleration sensor has been known. Further, a technique for measuring a relative change in attitude with respect to an absolute reference attitude angle by using an angular velocity sensor has been known. An attempt has been made to combine these sensors to more accurately and robustly measure the absolute attitude angle of an object to be measured.